The invention relates to a waste oil heater having a fuel control system, more particularly a waste oil heater of a type in which the fuel supply is automatically stopped when the fire in the burner suddenly extinguishes. Waste oil heaters are very important in the national conservation effort because it is estimated by the U.S. Department of Commerce, National Bureau of Standards that there is in excess of 1 and perhaps as much as 2 billion gallons per year of waste oil produced in the U.S., most of which is dumped on the ground, becoming a serious pollutant. Waste oil heaters burn this oil, without processing, cleanly and effectively.
In oil heaters, oil is supplied from a fuel tank to the burner, at which oil is vaporized by heat or atomized by ejection from a nozzle for completely burning oil. Waste oil generally includes many impurities which do not burn and cannot pass through a small conduit or valve. Therefore, when waste oil is to be burned, it is at first supplied to a vaporizer pan and is vaporized by heat thereat. That is, waste oil can be burned conveniently only in a vaporization type oil heater. Such oil heaters are provided with a pan to which the oil is fed and in which the oil is heat vaporized; the pan is commonly known as a "pot" or "retort". Consequently, such heaters are known as "pot type heat vaporizing oil heaters."
U.S. Pat. No. 4,116,614 discloses a waste oil heater of the type described above, in which waste oil is supplied to a vaporizer pan in a mantle by means of a pump operated by a reversible motor. The pump is connected through a rod to a cam block having short and long stroke channels, and the cam block is rotated by the motor. The rod engages either one or the other of the channels according to the rotational direction of the cam block, i.e., the fuel supply volumetric rate is regulated by the rotational direction of the motor. The rotational direction of the motor is selected by a thermostat.
The above waste oil heater is not sufficiently safe to meet U.S. standards. For example, if the fire in the burner extinguishes because the oil in the pan does not vaporize at a sufficient rate due to excessive contamination thereof or the oil being of too heavy a grade, the vaporizer pan continues to be filled with waste oil and oil overflows therefrom.
Accordingly, an object of the invention is to provide an oil heater of a type in which the fuel supply is stopped when the fire in the burner extinguishes.
Another object of the invention is to provide an oil heater as stated above, in which fuel control system is simply constructed and is accurately actuated.
Other objects and advantages of the invention will be apparent from the following description of the invention.